QSFP28 stands for "Quad Small Form-factor Pluggable 28." Each part of the name provides information about the form factor and characteristics of the optical transceiver:

1. Quad:

• Indicates that the transceiver has four independent channels. Each channel can operate at different data rates or work together for higher aggregate data rates.

2. Small Form-factor Pluggable (SFP):

• Refers to the standardized, hot-pluggable interface for optical transceivers. SFP modules are widely used in networking equipment, and the small form factor allows for high port density.

3. Pluggable 28:

• The "28" specifically refers to the data rate of each channel in gigabits per second (Gbps). In the case of QSFP28, each channel supports a data rate of up to 28 Gbps. With four channels working together, the total aggregate data rate can reach 100 Gbps.

QSFP28 modules are commonly used for high-speed data transmission in networking applications, including 100 Gigabit Ethernet connections. They are widely deployed in data centers, telecommunications networks, and other environments where high bandwidth and compact form factors are essential.